In the wake of the Obama administration's announcement of the cessation of missile defense plans for Europe, perhaps the President needs to review this very basic question.
To review the situation: the U.S. has finally developed effective defenses against ballistic missiles. They've been tested; they work. We have deployed two defense sites in the U.S., one in Alaska and one in California. But while these protect the U.S., they provide no defense for Europe. These defenses are not (at present) sufficient to defend against a massive Russian attack, which could involve hundreds of missiles. But they would be very effective against a rogue state such as North Korea or Iran.
Iran already has ballistic missiles of sufficient range to strike anywhere in the Middle East and many parts of Europe, and is developing ones that could strike the U.S. Despite their denials, they are also developing nuclear weapons. There is every reason to believe that by 2015, they will have a nuclear ICBM capacity.
Can Iran be deterred as the U.S.S.R. was during the Cold War? Maybe. But a culture that creates suicide terrorists cannot be counted on to be restrained by the mutual assurance of destruction. And even if they could, do we really want to have a Cold War with Iran? The world rejoiced when the Cold War ended because the threat of nuclear armageddon - even by accident - was reduced. Why would we want to return to that world?
Faced with this growing crisis a few years ago, the Bush administration proposed building missile defense sites in the Czech Republic and Poland to protect Europe. These are the sites that have been cancelled by President Obama. The apparent reason we are taking this reckless course of action is Russian worries about growing American hegemony in Eastern Europe.
The best possible result of all this would be a quid pro quo that brings Russian influence to bear against Iranian nuclear weapon development. I wonder if this move will really make a difference, though. Russia is in an odd position in all of this. On one hand, they oppose greater American power, and Iran is an expeditious ally in that effort. But Russia has its own Muslim problem, and surely fears nuclear-armed terrorists as much as, if not more than, we do. It is not clear how a marginal withdrawal of American power from Eastern Europe changes their calculus much.
Meanwhile, our own relations with our new Eastern European allies have suffered a blow. This is yet another example of the general rule that the American system is particularly prone to shafting allies, who have made agreements with one administration only to be disappointed by its successor. The Obama administration has made it clear that it considers it more important to court Russian favor than to have Poland and the Czech Republic as strategic partners. But the likelihood that this will ultimately lead to positive results for American foreign policy is slim.